1. Field of the Invention
This invention relates to the printing arts generally, and more particularly to hot-foil stamping presses such as are used for the process of foil stamping in the packaging industry.
2. Description of the Prior Art
The prior art includes purely mechanical arrangements in which strip material is advanced through, for example, a hot-foil stamping press, by means of the operation of cam-operated reciprocating levers which transmit their pulling force via chains and sprockets to individual shafts on which the rolls of strip material are mounted. Electromechanical clutches, between the chain-driven sprockets and the shafts on which the rolls of strip material are mounted, are alternately engaged and disengaged to intermittently advance the strip material.
Disadvantages of the prior art approach include the difficulty of setting up the press caused by the necessity to precisely locate the point of attachment of each chain to the reciprocating lever. Also, it is not possible to change the program sequence, that is, the sequence of short and long advances of the strip material, while the machine is in operation, and there is an upper limit, established by the range of motion of the reciprocating lever, on the length of strip material that can be advanced during each machine cycle. Furthermore, where the mechanism for advancing the strip material is integral with the hot-foil stamping press itself, it is not possible to utilize the press for other potential uses such as stripping or punching out scrap from die cut holes.
Unknown to the prior art is the provision of a digital stepping motor to drive a metering roll, with electric power supplied to the stepping motor by an electronic control means which has the capability of causing the shaft of the stepping motor to rotate through a predetermined, but readily alterable, program sequence.